| 云开地区前寒武系云开群变质岩系地质特征及其与金矿成矿的关系 |
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| 引用本文：邵军.1991.云开地区前寒武系云开群变质岩系地质特征及其与金矿成矿的关系[J].地球学报,12(3):19-30. |
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| 中文摘要:云开地区前寒武系云开群变质岩系的主体是片岩类、片麻岩类、硅质岩类及变粒岩。其原岩是一套陆源碎屑类复理石沉积建造,该岩系经历了加里东期的绿帘石角闪岩相—角闪岩相的前进变质作用和海西期的绿片岩相—绿帘石角闪岩相的退变质作用(动力变质作用)。在构造—岩浆作用下,部分变质岩遭受了强烈的混合岩化作用,形成了各种形态的混合岩及混合花岗岩。变质岩系富含硅、铝、砷、硼及轻稀土元素,贫钾、钠、镍、铬、钴及重稀土元素,且含金量随岩石含Al_2O_3、有机碳量的增加而增高,是本区最主要的金矿源层。 在变质作用和构造—岩浆作用过程中,产生了Cl—K—Na型和S—K—Na型成矿热液流体,并活化、萃取了矿源层中的金,以氯和(或)硫络合物的形式迁移。在成矿的有利部位(如断裂破碎带、糜棱岩带等),金沉淀形成了矿床。 |
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| PRECAMBRIAN METAMORPHIC ROCK SERIES AND ITS RELATION TO GOLD MINERALIZATION IN YUNKAI AREA |
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| Abstract:The precambrian metamorphic rock series of Yunkai group in Yunkai Mt. principally consist of schistes,gneisses, siliceous rocks and leptynites. They had experienced the progressive metamorphism of epidote amphiboli-te-amphibolite facies in the Caledonian cycle and retrogressive metamorph ism (regional dynamometamorphism) of greenschist-epidote amphibolite facies in the Hercynian cycle. The rock series were locally migmatized to various migmatites and migmatic granite by tectonomagmatic activity. The metamorphic rocks are rich in Si, Al, B, As, LREE, and poor in K, Na, Cr,Co and HREE. The origional rocks are terrigenous clastic flyschoid formation. The gold content varies with the content of Al2O3 and organic carbon of metamorphic rocks. The rock series of Yunkai group are the chief gold source beds in this area.The hydrothermal fluids of Cl-K-Na and S-K-Na type are produced by metamorphism and tectonomagmatic activities. The gold were activated and extracted from the source beds by the hydrothermal fluids and were migrated in the form of Cl-and/or S-complexes. Finally, the gold concentrated and deposited in the favorable sites such as fault ruptured zones and mylo-nitized zones to form gold deposits. |
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